[R] can't find 'predict.loess' in a loop
Uwe Ligges
ligges at statistik.tu-dortmund.de
Thu Dec 22 09:55:40 CET 2011
See methods(predict) and find that methods are hidden in the Namespaces
and are ought to be accessed by the generic. If you really want to
access it explicitly (which i not intended by design), see help(":::")
Your code is not reproducible, hence we cannot help in detail.
Uwe Ligges
On 22.12.2011 09:39, Stuart Leask wrote:
>
> Season's Greetings.
>
> I am using 'predict' in a loop, but it is behaving unexpectedly, so I am more explicit and use 'predict.loess', and R says it can't find it. Even if I explicitly load the stats library, which is already in the search path.
>
> Any ideas?
> This is odd, because if I use RB& LB from a different dataset, it works fine...
>
>
> Stuart
>
> *********************************************************************
> *************************
> Original problem:
>
>> j<-0 # start an iteration counter
>> while(j<30) # (max 30 iterations)
> +
> + {
> +
> + lenRB<-length(RB) # number of rows in original RB
> + lenLagRB<-(j+1):lenRB # row numbers for 'lagged' RB
> + lenLagRB0<-1:(lenRB-j) # row numbers for 'unlagged' RB
> + RBj<-RB[lenLagRB] # create a 'lagged' RB of this length
> + LBj<-LB[lenLagRB] # create a 'lagged' LB of this length
> + RB0<-RB[lenLagRB0] # create an 'unlagged', shortened RB of this length
> + LB0<-LB[lenLagRB0] # create an 'unlagged' LB of this length
> +
> + cor.j<-cor(RBj,LB0) # check RB lagged& LB have low correlation
> + if(abs(cor.j)<0.01) # if so...
> +
> + {
> +
> + RELBj<-100*(RBj-LB0)/(RBj+LB0) # ...generate index for lagged pair
> + RELB0<-100*(RB0-LB0)/(RB0+LB0) # generate index for unlagged pair
> +
> + Lag.lo<-loess(RBj~RELBj,span=sp, family=("symmetric"), degree=2) # close approx of lowess!
> + Real.lo<-loess(RB0~RELB0,span=sp, family=("symmetric"), degree=2)
> + Lag.pr<-predict(Lag.lo, data.frame(x=seq (-80,80,1))) # predict for uniform index scale
> + Real.pr<-predict(Real.lo,data.frame(x=seq (-80,80,1)))
> +
> + Diff.pr<-Real.pr-Lag.pr # difference plot
> + lines (Diff.pr~seq(-80,80,1),pch=1,cex=0.25,col=1)
> +
> + }
> +
> + j<-j+1 # increment counter and repeat
> + }
> Error in model.frame.default(formula = Diff.pr ~ seq(-80, 80, 1), na.action = NULL) :
> variable lengths differ (found for 'seq(-80, 80, 1)')
> In addition: Warning messages:
> 1: 'newdata' had 161 rows but variable(s) found have 250 rows
> 2: 'newdata' had 161 rows but variable(s) found have 250 rows
>
> ****************************
> Make it more explicit I want to use predict.loess:
>
>> j<-0 # start an iteration counter
>> while(j<30) # (max 30 iterations)
> +
> + {
> +
> + lenRB<-length(RB) # number of rows in original RB
> + lenLagRB<-(j+1):lenRB # row numbers for 'lagged' RB
> + lenLagRB0<-1:(lenRB-j) # row numbers for 'unlagged' RB
> + RBj<-RB[lenLagRB] # create a 'lagged' RB of this length
> + LBj<-LB[lenLagRB] # create a 'lagged' LB of this length
> + RB0<-RB[lenLagRB0] # create an 'unlagged', shortened RB of this length
> + LB0<-LB[lenLagRB0] # create an 'unlagged' LB of this length
> +
> + cor.j<-cor(RBj,LB0) # check RB lagged& LB have low correlation
> + if(abs(cor.j)<0.01) # if so...
> +
> + {
> +
> + RELBj<-100*(RBj-LB0)/(RBj+LB0) # ...generate index for lagged pair
> + RELB0<-100*(RB0-LB0)/(RB0+LB0) # generate index for unlagged pair
> +
> + Lag.lo<-loess(RBj~RELBj,span=sp, family=("symmetric"), degree=2) # close approx of lowess!
> + Real.lo<-loess(RB0~RELB0,span=sp, family=("symmetric"), degree=2)
> + Lag.pr<-predict.loess(Lag.lo, data.frame(x=seq (-80,80,1))) # predict for uniform index scale
> + Real.pr<-predict.loess(Real.lo,data.frame(x=seq (-80,80,1)))
> +
> + Diff.pr<-Real.pr-Lag.pr # difference plot
> + lines (Diff.pr~seq(-80,80,1),pch=1,cex=0.25,col=1)
> +
> + }
> +
> + j<-j+1 # increment counter and repeat
> + }
> Error: could not find function "predict.loess"
>
> ****************
>
>> search()
> [1] ".GlobalEnv" "nshd"
> [3] "package:foreign" "package:stats"
> [5] "package:graphics" "package:grDevices"
> [7] "package:utils" "package:datasets"
> [9] "package:methods" "Autoloads"
> [11] "package:base"
>> ?predict.loess
>
> ... Confirms that predict.loess is in the path, and can be accessed.
> Only not within the loop?
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